Journal of Medicinal Chemistry (2000), vol. 43, no. 9, p. 1664-669 discloses derivatives of GLP-1(7-37) that are double-acylated at K26,34.
WO 2011/080103 A1 discloses a number of double-acylated GLP-1 derivatives acylated at K26 and at K37.
WO 99/43706 A1 discloses a number of mono- and double-acylated GLP-1 derivatives.
WO 98/08871 A1 discloses a number of GLP-1 derivatives including some that are double-acylated.